Heat resistant polymers of oxidized styrylphosphine

ABSTRACT

Homopolymers, copolymers and terpolymers of a styrene based monomer are prepared by: 
     (1) polymerizing at least one oxidized styrylphosphine monomer selected from the group of: 
     (C 6  H 5 ) 2  P(O)N═P(C 6  H 5 ) 2  C 6  H 4  CH═CH 2 , 
     (c 6  h 5  o) 2  p(o)n═p(c 6  h 5 ) 2  c 6  h 4  ch═ch 2 , 
     (c 6  h 5 ) 2  c 3  n 3  n═p(c 6  h 5 ) 2  c 6  h 4  ch═ch 2  and 
     (C 6  H 5 ) C 3  N 3  [N═P(C 6  H 5 ) 2  C 6  H 4  CH═CH 2  ] 2  ; or 
     (2) polymerizing p-diphenylphosphinestyrene and then oxidizing said polymerized p-diphenylphosphinestyrene monomer with an organoazide selected from the group of (C 6  H 5 ) 2  P(O)N 3 ,(C 6  H 5  O) 2  P(O)N 3 ,(C 6  H 5 ) 2  C 3  N 3  (N 3 ) and C 6  H 5  C 3  N 3  (N 3 ) 2 . Copolymers can also be prepared by copolymerizing styrene with at least one oxidized styrylphosphine monomer selected from the group of: 
     (C 6  H 5 ) 2  P(O)N═P(C 6  H 5 ) 2  C 6  H 4  CH═CH 2 , 
     (c 6  h 5  o) 2  p(o)n═p(c 6  h 5 ) 2  c 6  h 4  ch═ch 2 , 
     (c 6  h 5 ) 2  c 3  n 3  n═p(c 6  h 5 ) 2  c 6  h 4  ch═ch 2  and 
     (C 6  H 5 )C 3  N 3  [N═P(C 6  H 5 ) 2  C 6  H 4  CH═CH 2  ] 2

ORIGIN OF THE INVENTION

The invention described herein was made in the performance of work undera NASA contract and subject to the provisions of Section 305 of theNational Aeronautics and Space Act of 1958, Public Law 85-568(72 stat435; 42 USC 2457).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to flame-resistant, non-toxic vinylpolymers which contain phosphazene groups. The polymers of the presentinvention do not emit any toxic or corrosive products when they areoxidatively degraded.

2. Description of the Prior Art

Presently, there are available a number of flame resistant materials andmaterials combinations. The vast majority of these, however, produceunacceptably large amounts of toxic and corrosive substances whensubjected to oxidative thermal decomposition even in the absence of aflame. The toxic product formation is as great a hazard as a fire itselfin any confined location and is particularly dangerous in spacecapsules, aircraft, or submarines, where egress or ventilation cannot bereadily accomplished. The applicability of the few polymericcompositions which are flame resistant and do not form toxic degradationproducts, on the other hand, is limited because of cost, often poorprocessibility, and the fact that they do not lend themselves tomodifications to improve deficiencies in physical or mechanicalcharacteristics. These materials are based on highly condensed aromaticstructures which during oxidative thermal decomposition form chars inhigh yields, and thus, release combustible decomposition products at toolow a rate to support a flame.

All other flame resistant compositions derive this property from thepresence of elements, which are known to act as flame retardants. Theseare elements of the third, fifth, and seventh main groups of theperiodic table, specifically boron, nitrogen, phosphorus, antimony, andthe halogens. Of these, only nitrogen, phosphorus, and the halogens aredirectly bonded in or to the polymer backbone. Boron and antimonynormally are physically admixed with the flame resistant compositions,the former usually as a salt of boric acid, the latter either as itsoxide or oxychloride. Yet internal bonding is preferable to admixturesince additives are subject to removal by physical and chemicalprocesses such as abrasion and washing.

The halogenated flame resistant materials such aspolytetrafluoroethylene, copolymers of perfluoropropene and vinylidenefluoride, or polyvinylchloride contain the flame retardant bonded to thepolymer backbone. Some of these materials exhibit very good flameresistance and have other desirable characteristics such as goodmechanical properties and good processibility. However, these materialsupon oxidative thermal decomposition produce copious quantities ofhighly toxic and corrosive gases. Moreover, the thermal decompositionprocess can take place long before flame temperatures are reached.Polyvinylchloride, for examples, was found to lose practically all ofthe chlorine present (56.7%) in the form of toxic and corrosive hydrogenchloride at about 280° C leaving a residue which was combusted by excessair in a strongly exothermic reaction (Boettner et al.; Organic Coatingsand Plastics Chemistry, Preprints, 28, No. 1, 311, April 1968).Polytetrafluoroethylene (Teflon), when exposed to elevated temperaturein the presence of air, was shown by K. L. Paciorek et al, Final Report,Part I, Contract NASW-1921, August 1970; CR 114357 and K. L. Paciorek etal., Final Report, Part II, Contract NASW-1921, June 1971 to formcarbonyl fluoride, which is hydrolyzed to toxic hydrogen fluoride andcarbon dioxide, if water is also present. Fluorinated polymers, whichalso contain hydrogen, e.g., the copolymer of perfluoropropene andvinylidene fluoride (Viton, Fluorel) release hydrogen fluoride directlyif not judiciously compounded. One of the reasons for this behavior isthat halogens can be present in a polymer only as singly bondedmoieties, and consequently cannot be incorporated into the normally morestable polymer backbone. Accordingly, the fire retarding element can beremoved from the material by such simple reactions asdehydrohalogenation. This type of action is unlikely to occur in thecase of an element which is either multiply bonded in the backbone orwhich is a part of an aromatic structure, thus capable of charringwithout volatilization upon exposure to a flame or elevatedtemperatures.

The remaining two of the above enumerated elements known to act as flameretardants are nitrogen and phosphorus, both of which are multivalent,thus can be incorporated in a polymer backbone, and are capable ofmultibonding. The flame retarding capability of triazine type compounds,and especially of phosphorus-nitrogen combinations, has beem amplydocumented. U.S. Pat. No. 2,514,268 (1950); Brit. Pat. No. 638,434(1950); R. C. Nametz, Ind. Engin. Chem., 59, 99 (1967); G. C. Tesoro etal, 155th ACS Meeting, Organic Coatings and Plastics Chemistry,Preprints, 28, No. 1, 243, April 1968; H. R. Allcock, C&EN, Apr. 22,1968, 68-81, and C. E. Miles et al, 155th ACS Meeting, Organic Coatingsand Plastics Chemistry, Preprints, 28, No. 1, 237, Apr. 1968. The exactnature of their action as flame retardants either alone or incombination is not known. Either one of the elements would be expectedto interfere in the free radical chain reactions propagating the flames.More importantly, however, both are known to form strong chars andaccordingly do not contribute fuel to the flame. Such chars, inaddition, insulate thermally the lower layers of the polymers thusinhibiting pyrolysis, and depress or prevent the access of oxygen to thesubsurface. Phosphorus, when contained in an aromatic structure or whensubstituted by aromatic moieties such as phenyl groups, formsmechanically particularly strong chars, which have been shown to exhibitthe above properties.

Flame-resistant polymers containing phosphazene repeating units in thepolymer backbone are known, see for example U.S. Pat. Nos. 3,702,837,3,888,799 and 3,896,058. However, these polymers lack the mechanicalproperties and good processability possessed by vinyl polymers such aspolystyrene. As a result, these polymers have a limited field of use.

Accordingly, thre exists a need for flame resistant polymers whosedegradation products are both non-toxic and non-corrosive whichpossesses mechanical and processing properties similar to those of knownvinyl polymers.

SUMMARY OF THE INVENTION

It is an object of the present to prepare vinyl polymers which areflame-resistant and whose degradation products are non-toxic andnon-corrosive.

It is another object of the present invention to provide a process forpreparing flame-resistant homopolymers, copolymers and terpolymers.

Still another object of the present invention is to provide aflame-resistant, non-toxic polymer which may safely be used in confinedlocations where there is inadequate ventilation.

Briefly, these objects and other objects of the present invention ashereinafter will become more readily apparent can be attained bypolymers prepared by polymerizing compounds having the formula:

    R - N ═ P (C.sub.6 H.sub.5).sub.2 (C.sub.6 H.sub.4) CH ═ CH.sub.2

wherein R is an organic moiety selected from the group of:

    (C.sub.6 H.sub.5).sub.2 P(O)--, (C.sub.6 H.sub.5 O).sub.2 P(O)--, (C.sub.6 H.sub.5).sub.2 C.sub.3 N.sub.3 --,

mixtures thereof or by polymerizing a compound having the formula C₆ H₅C₃ N₃ [N═P(C₆ H₅)₂ (C₆ H₄)CH═CH₂ ]₂ ; or by reacting a polymer of theformula: ##STR1## with an organic azide selected from the group of (C₆H₅)₂ P(O)N₃, (C₆ H₅ O)₂ P(O)N₃, (C₆ H₅)₂ (C₃ N₃)(N₃), (C₆ H₅) C₃ N₃(N₃)₂ and mixtures thereof. By judicious choice of the reactantshomopolymers, copolymers and terpolymers can be prepared by polymerizingmixtures of the above azido oxidized styrylphosphine monomers and bypolymerizing one or more of these monomers with a vinyl monomer such asstyrene. Alternatively, the interpolymer can be prepared by firstpolymerizing diphenyl-p-styryl phosphine either alone or with anothervinyl monomer to prepare a polymer. The resulting polymer is thenreacted with an organo azide to introduce phosphazene groups into theresultant polymers.

The polymers of the present invention can be molded into shaped articlesand films using conventional techniques.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The polymers of the present invention are vinyl based polymerscharacterized by containing pendant radicals containing phosphazenegroups. The polymers can be prepared by two techniques in which thefirst route involves the polymerization of at least one organoazideoxidized styrylphosphine monomer, and the second route involves thepreliminary polymerization of styrylphosphine monomer and subsequentoxidation of the pendant phosphine moieties in the polymer with at leastone organoazide. In the context of the present invention the termstyrylphosphine monomer not only includes the ortho, meta and paraisomers of styryldiphenylphosphine, but also includes othervinylaromatic diphenyl phosphines such asvinylnaphthyldiphenylphosphine. Furthermore, each aromatic residue inthe monomer can be substituted by one or more substituents such asalkyl, preferably lower alkyl of one to six carbon atoms, nitro, halosuch as carbon, bromo and iodo, and the like. In the first route, theappropriate monomer(s) is prepared by oxidatively reacting astyrylphosphine compound with an organoazide. The type of organoazideselected for the reaction is not critical. Suitable organoazides includediphenylphosphinylazide, (C₆ H₅)₂ P(O)N₃ ; diphenylphosphoryl-azide, (C₆H₅ O)₂ P(O)N₃ ; 2-azido-4,6-diphenyl-5-triazine, (C.sub. 6 H₅)₂ C₃ N₃(N₃); 2,4-diazido-6-phenyl-s-triazine, (C₆ H₅)C₃ N₃ (N₃)₂,trimethylsilylazide, triphenylsilylazide and phenylazide. The reactionof the styrylphosphine with the organoazide results in the oxidation ofthe trivalent phosphorous atom to the pentavalent state in the form ofan unsaturated P═N linkage known as a phosphazene group.

The basic styrylphosphine monomer of the present invention can beprepared by any convenient and accetable technique. In one embodimentstyrylphosphine can be prepared by synthesizing a reactive Grignardagent of chlorostyrene. The Grignard agent is then reacted with dephenylhalophosphine to complete the preparation. In another embodiment anactive lithium intermediate can be prepared by reacting thechlorostyrene with an organo lithium compound such as butyllithium, andthen reacting the reagent prepared with diphenylhalophosphine.

The oxidized monomer of the present invention can be prepared by mixingstoichiometric quantities of organoazide and styrylphosphine in asolvent. Suitable solvents include dialkyl ethers such as diethyl ether,dripropyl ether and the like; tetrahydrofuran, acetonitrile; aromatichydrocarbons such as benzene, xylene, toluene and the like andhalohydrocarbons such as chloroform, methylenechloride and the like. Thereaction temperature is not critical, but usually ranges from 0° C toambient temperature depending on the activity of the azide. Slowreacting azides may require temperatures as high as refluxingtemperatures. The reaction pressure also is not critical. During thecourse of the reaction nitrogen is evolved as evidence of thedestruction of the azido compound. The desired oxidized monomer can thenbe obtained by any suitable precipitation or solvent removal technique.In some instances oxidation of styrylphosphine monomer results directlyin the formation of a homopolymer without the isolation of the oxidizedmonomer. Thus, when styrylphosphine is reacted with diphenylphosphinylazide, a polymeric material of the formula: ##STR2## is obtained, andthe oxidized monomer,

    (C.sub.6 H.sub.5).sub.2 P(O)N═P(C.sub.6 H.sub.5).sub.2 C.sub.6 H.sub.4 CH═CH.sub.2

is not isolated. Diphenylphosphoryl azide when reacted withstyrylphosphine also results in the formation of some polymer material,however, not to the extent obtained with diphenylphosphinylazide.Reaction of styrylphosphine with the other oxidizing agents does notresult in the formation of polymer. Only the desired oxidized monomer isobtained. It thus appears that there is a relationship between the easeor rate of oxidation of styrylphosphine by an azide and the ability ofthe azide to function as a polymerization catalyst. The triazene azides,which promote the oxidation reaction very quickly, do not seem topromote the polymerization reaction. It may be that during oxidation atransition state exists which activates the double bond ofstyrylphosphine so that it undergoes polymerization.

The polymerization reaction of the invention as it relates either to thepolymerization of an oxidized styrylphosphine monomer or to thepolymerization of styrylphosphine monomer which is later oxidized withat least one organoazide, can be conducted by bulk polymerizationtechniques. An alternative technique can be the homopolymerization orcopolymerization of the styrylphosphine monomer in an organic solventsuch as benzene or toluene, with a radical initiator such as2,2'-azobis-(2-methylpropionitrile). This reaction is usually conductedunder an inert atmosphere of nitrogen argon or the like at 50°-100° Cfor 4-200 hours. In conducting the bulk polymerization of either theoxidized or unoxidized styrylphosphine monomer, it is necessary toachieve a polymer product having as high a molecular weight as possiblein order to obtain a polymeric material having satisfactory molding andfilm forming characteristics as well as a satisfactory melting orsoftening range. While the molecular weight can widely vary themolecular weights of the polystyrylphosphine usually ranges from 10,000to 100,000. These values, as determined with an osmometer, are numberaverage molecular weights. Any convenient method can be used for thebulk polymerization of both oxidized and unoxidized styrylphosphinemonomer. In one embodiment of the bulk polymerization process, a desiredquantity of a monomer or desired quantities or more than one monomer aresealed in an enclosed reactor and heated to 60° C to 250° C, preferably60° C to 250° C to effect polymerization. If necessary, a radicalinitiator such as 2,2'-azobis(2-methylpropionitrile) can be used eitherwith or without the presence of an organic solvent. The reaction isnormally conducted from 1/3 to 288 hours, preferably 0.5 to 24 hours. Inmany instances, longer reaction times can be used at lower temperaturesin the indicated range. Once the reaction is complete, the reactionresidue is treated with an appropriate solvent to remove soluble polymerproducts therefrom. Suitable solvents for the extraction includehalohydrocarbons such as chloroform and the like. The precipitatedpolymer is then isolated by any convenient technique such as filtrationand then dried.

In any embodiment of the bulk polymerization procedure, a desiredquantity of monomer or desired quantities of more than one monomer areplaced in an evacuated reactor. After evacuation of the reactor, usuallya glass ampoule, to a suitable pressure of about 10⁻³ mm, the ampoule isthen heated to 60° C to 250° C, preferably 150° C to 230° C to effectpolymerization over a time period of 1/3 to 288 hours, preferably 0.5 to24 hours. Instead of conducting the reaction under a vacuum the reactioncan be conducted under an inert atmosphere such as nitrogen, or thelike. After the reaction is complete, the desired polymer product can beisolated as described supra.

By the use of a suitable bulk polymerization procedure, an oxidizedstyrylphosphine monomer such as

    (C.sub.6 H.sub.5 O).sub.2 P(O)N═P(C.sub.6 H.sub.5).sub.2 C.sub.6 H.sub.4 CH═CH.sub.2,

    (c.sub.6 h.sub.5 o).sub.2 p(c.sub.6 h.sub.5).sub.2 c.sub.6 h.sub.4 ch═ch.sub.2,

    (c.sub.6 h.sub.5).sub.2 c.sub.3 n.sub.3 n═p(c.sub.6 h.sub.5).sub.2 c.sub.6 h.sub.4 ch═ch.sub.2, or

    (C.sub.6 H.sub.5)C.sub.3 N.sub.3 [N═P(C.sub.6 H.sub.5).sub.2 C.sub.6 H.sub.4 CH═CH.sub.2 ].sub.2

can be polymerized to yield homopolymers having a molecular weight rangeof 10,000 to 100,000. The polymerization reactions for the homopolymerscan be conducted at a temperature ranging from 130° C to 230° C. For thehomopolymerization of (C₆ H₅ O)₂ P(O)N═P(C₆ H₅)₂ C₆ H₄ CH═CH₂, thepolymerization temperature preferably ranges from 150° C to 160° C. Ifthe polymerization temperature is elevated to about 230° C,cross-linking of the polymer product obtained occurs. Polymeric materialhaving a molecular weight range of 50,000 to greater than 100,000 can beobtained. The homopolymer is oxidatively stable up to temperatures ofabout 275° C. For the homopolymerization of (C₆ H₅)C₃ N₃ [N═P(C₆ H₅)₂ C₆H₄ CH═CH₂ ]₂, the polymerization temperature preferably ranges from 130°C to 160° C and always provides a cross-linked material because of thedifunctionality of the monomer. If the reaction is conducted at atemperature of about 160° C, the resulting product is mostly chloroforminsoluble indicating a highly cross-linked polymer product. The polymerproduct obtained, when heated, starts to thermally decompose at about300° C. However, the char yield upon decomposition stabilizes at 41% atabout 550° C, and does not seem to decrease further at temperatures upto 610° C.

Copolymeric materials can be prepared by reacting two of the oxidizedstyrylphosphine monomers of the present invention in any suitable bulkpolymerization procedure at a temperature ranging from 150° C to 235° Cfor 0.5 to 5.0 hours at mole ratios ranging from 1:1 to 1:10. Includedwithin the scope of the copolymerization reaction are bothstyrylphosphine monomer and styrene. From analysis of the solublefractions of the polymers, the molecular weight ranges from 15,000 to34,000.

In one embodiment of the copolymerization aspect of the inventiondiphenyl-p-styrylphosphine can be bulk polymerized with

    (C.sub.6 H.sub.5).sub.2 C.sub.3 N.sub.3 N═P(C.sub.6 H.sub.5).sub.2 C.sub.6 H.sub.4 CH═CH.sub.2

in any suitable relative amounts to produce a copolymer of good thermalstability. Usually, however, equimolar quantities of reacting monomersare used. In another embodiment of the copolymerization procedureappropriate quantities of

    (C.sub.6 H.sub.5)C.sub.3 N.sub.3 [N═P(C.sub.6 H.sub.5).sub.2 C.sub.6 H.sub.4 CH═CH.sub.2 ].sub.2

can be reacted with

    (C.sub.6 H.sub.5).sub.2 C.sub.3 N.sub.3 N═P(C.sub.6 H.sub.5).sub.2 C.sub.6 H.sub.4 CH═CH.sub.2

usually in a mole ratio of 1:20, to form a polymeric residue containingboth chloroform soluble and insoluble polymers. Both insolube andsoluble portions of the copolymer can be used in the preparation ofmolded articles.

Terpolymeric polymeric materials can also be prepared by coreactingthree oxidized styrylphosphine monomers by any suitable bulkpolymerization procedure at a temperature ranging from 165° C to 230° C.The reacting monomers can be polymerized in any appropriate quantities.However, when the difunctional monomer (C₆ H₅)C₃ N₃ [N═P(C₆ H₄)₂ C₆ H₄CH═CH₂ ]₂, is used as a reactant, it should not be used in proportionalamounts greater than 10 mole %, i.e., no greater than a ratio of 1:10relative to the other monomers. Difunctional monomer containing polymerscan be molded into transparent discs at 350° F and a pressure of about750 lbs. Since the polymer product obtained when the difunctionalmonomer is used as a reactant, is solvent insoluble, molecular weightscan not be determined. However, the minimum molecular weight is believedto be about 20,000. In a preferred embodiment of the present inventionterpolymer can be prepared by reacting 50 to 90 mole % of

(C₆ H₅ O)₂ P(O)N═P(C₆ H₅)₂ C₆ H₄ CH═CH₂, 36 to 15 mole percent of

(C₆ H₅)₂ C₃ N₃ N═P(C₆ H₅)₂ C₆ H₄ CH═CH₂ and 10 to 2 mole percent of

(C₆ H₅)C₃ N₃ [N═P(C₆ H₅)₂ C₆ H₄ CH═CH₂ ]₂.

Polystyrylphosphine materials of the present invention can also beprepared by a second route as mentioned earlier by first bulkpolymerizing styrylphosphine. Essentially the same time and temperatureconditions as described earlier for the bulk polymerization of theoxidized styrylphosphine can be employed for the bulk polymerization ofstyrylphosphine. The molecular weight range for the polymerized productgenerally ranges from 10,000 to 67,000. The polystyrylphosphine onceobtained, is then oxidatively reacted by any suitable procedure with anappropriate organoazide to form the desired phosphazene homopolymer oris oxidatively reacted with two or more organoazides to form appropriatecopolymers and terpolymers. The oxidation reaction is conducted in anorganic solvent wherein suitable solvents include tetrahydrofuran,diglyme, benzene, toluene, chloroform and the like. Reaction temperatureis not critical and is usually ambient temperature. Normally, the amountof azide employed is that amount sufficient to react with all of thephosphine units in the polymer. Thus, for instance, a homopolymer of theformula ##STR3## can be prepared by reacting diphenylphosphoryl azidewith polystyrylphosphine. The product prepared by the oxidation ofpreformed polystyrylphosphine can be readily molded to form articles.Moreover, polymer films can be cast from solution onto an aluminumsurface. It is believed that partially oxidized polymer ##STR4## shouldbe also amenable to fabrication of useful articles; however, this typeof material would be expected to undergo oxidation to the oxide ##STR5##

Copolymers can be prepared by reacting th preformed polystyrylphosphinewith two organoazides in appropriate quantities in much the same mannerpolystyrylphospine is reacted with only one organoazide. When twoorganoazides are reacted with the preformed polystyrylphosphine, theycan be reacted in any relative amounts either simultaneously orconsecutively. Thus, in a preferred embodiment of this aspect of theinvention, from 50 to 90 mole percent of

    (C.sub.6 H.sub.5 O).sub.2 P(O)N.sub.3

is reacted with a unit amount of styrylphosphine polymer followed by 50to 10 mole % of

    (C.sub.6 H.sub.5).sub.2 C.sub.3 N.sub.3 (N.sub.3)

in a manner similar to that used above for the preparation ofcopolymers, terpolymers can be prepared by reacting the desired amountsof three organoazides with a unit amount of polystyrylphosphine. In theterpolymers if monofunctional azides are employed, these can be used inequal mole percent or any other percentages depending on the desiredproperties of the final polymer. All of the three azides can be addedsimultaneously. However, if a difunctional azide is employed to yield acrosslinked product, it has to be added after the monoazides havereacted to avoid intramolecular reactions, i.e., joining of adjacentsites on the same polymer chain. An especially useful terpolymer whichis amenable to molding and film casting and which has high molecularweight is high melting and yet soluble, can be prepared as follows:##STR6## (The above reaction sequence is not to be interpreted asmeaning that block copolymers are formed by this procedure.)

In another aspect of the invention phosphazene group containing styrylpolymers can be obtained by copolymerizing styrene with the reactivemonomer(s) in either of the polymerization procedures of the invention.Other suitable comonomers include those which are amenable tocopolymerization with styrene such as butadiene. Thus, when an oxidizedstyrylphosphine monomer or more than one oxidized styrylphosphinemonomer is reacted with styrene, from 20 to 95 mole % of styrene can bereacted with 80 to 5 mole % of oxidized styrylphosphine monomer(s). Inthe situations where the object polymers are prepared by oxidizing thependant phosphine groups of preformed styrylphosphine polymers, from 20to 95 mole % of styrene can be reacted with from 80 to 5 mole % ofstyrylphosphine monomer. Preferred embodiments of copolymers derivedfrom the polymerization of styrene with an oxidized styrylphosphinemonomer include a copolymer having the formula: ##STR7## wherein X is50-10 mole percent and y is 50-90 mole percent; and a copolymer of theformula: ##STR8## wherein x is 50-10 mole percent and y is 50-90 molepercent.

According to thermal gravimetric analysis data, the homopolymers,copolymers and terpolymers of the invention are thermally stable. Someof the homopolymers appear to be thermally stable up to 350° C. In fact,under conditions which cause polystyrene to explode, i.e. a temperatureof 540° C under a dynamic flow of oxygen preheated to 540° C, a Nomexcloth impregnated with 32% of --(C₆ H₅)₂ P(O)N═P(C₆ H₅)₂ C₆ H₄ CH═CH₂]_(x) gave an 86% residue.

The phosphazene group containing styryl polymers of the presentinvention are characterized by having satisfactory molding and filmforming characteristics as well as being non-toxic when thermallydecomposed. The polymers are self-extinguishing when ignited in air.Moreover, the polymeric materials are heat resistant and possess higherchar yields than styrene. The polymeric materials of the presentinvention can be used in the manufacture of components of systems suchas space crafts, air crafts, and the like from which egress in thepresence of fire is difficult or impossible. In addition co- andterpolymers obtained by copolymerization of the styrylphosphine oxidizedmonomer with other conventional monomers can be employed for the sameapplications, mainly as structural materials, where styrene copolymersare used with the advantage that the presence of the chemically bondedphosphorus will render these materials more flame resistant than is thecase usually with styrene based compositions.

Having generally described this invention, a further understanding canbe obtained by reference to certain specific examples which are providedherein for purposes of illustration only and are not intended to belimiting unless otherwise specified.

I. PREPARATION OF ORGANOAZIDE REACTANTS

All solvents used were reagent grade and were dried and distilled priorto use. All operations involving moisture or air sensitive materialswere carried out either in an inert atmosphere enclosure (VacuumAtmospheres Model HE-93B), under nitrogen by-pass, or in sealedampoules. The commercially available starting materials were usuallypurified by distillation, crystallization, or other appropriate means.All molecular weights were determined using a Mechrolab Osmometer Model302.

The melting points of all solid monomers were determined in nitrogenfilled sealed melting point capillaries, softening and melting points ofthe polymers were obtained using a Fisher-Johns apparatus.

EXAMPLE 1 PREPARATION OF 2-CHLORO-4-DIPHENYL-TRIAZINE

The procedure used was based on the method of Jones et al, AD 229453,Sept. 1959. A stirred mixture of magnesium turnings (24.3 g, 0.935 mol)and a crystal of iodine in ether (150 ml), was added a solution ofbromobenzene (155.3 g, 0.985 mol) in ether (100 ml) under a nitrogenatmosphere over a period of 3.75 hr at such a rate as to maintain agentle reflux. Thereafter, the mixture was refluxed for 2.5 hr. TheGrignard reagent thus prepared was then cooled and transferred to anaddition funnel and added with stirring to a solution of cyanuricchloride (70 g, 0.38 mol) in benzene (500 ml) at 4°-15° C (ice bathcooling) over a period of 1.25 hr. After stirring overnight the mixturewas refluxed for 4 hr, cooled, and filtered. The filtrate was evaporatedto dryness using a Rinco evaporator yielding 136.5g of crude productmixture. This mixture was distilled in vacuo at 0.007 mm. The desiredproduct, bp 140°-152° C, 63.5 g (62% yield), was crystallized threetimes from heptane yielding pure 2-chloro-4,6-diphenyl-s-triazine, 46.1g (45% yield), mp 136°-138° C.

EXAMPLE 2 PREPARATION OF 2-AZIDO-4,6-DIPHENYL-TRIAZINE

A suspension of 2-chloro-4,6-diphenyl-s-triazine (30 g, 0.112 mol),sodium azide (12.86 g, 0.199 mol) and lithium azide (1.24 g, 0.025 mol)in acetonitrile (550 ml) was stirred at room temperature for 11 days.After filtration, the filtrate on evaporation yielded 6.9 g of2-azido-4,6-diphenyl-s-triazine, mp 115°-117° C. The residue onextraction with hot heptane, followed by crystallization from heptane,gave an additional 20 g quantity having a mp of 114°-116° C bringing thetotal yield of 2-azido-4,6-diphenyl-s-triazine to 26.9 g (88% yield).The melting point and infrared spectrum were identical with that of anauthentic sample.

EXAMPLE 3 PREPARATION OF 2, 4-DICHLORO-6-PHENYL-S-TRIAZINE

This compound was prepared via a two-step reaction using a combinationof two literature procedures. A mixture of2,4-diamino-6-phenyl-s-trazine (150 g, 0.802 mol) and 90% sulfuric acid(600 ml) was heated with stirring in an oil both maintained at 105°-124°C for 20.5 hr. After cooling to 70° C, the mixture was poured over 5000ml crushed ice. Upon standing overnight in the refrigerator, thesolution deposited a white solid which was collected, washed with water(3000 ml) and dried to give 128.1 g, (84% yield) of2,4-dihydroxy-6-phenyl-s-trazine, mp 290°-294° C (dec.); lit. 289°-290°C (dec). (Belgian Pat. No. 634,399 (1964); Chem. Abstracts, 61, 671(1964)).

To a stirred mixture of 2,4-dihydroxy-6-phenyl-s-triazine (45 g, 0.238mol) and thionyl chloride (250 ml) was added dropwise under anhydrousconditions dimethylformamide (50 ml) over a period of 10 min.Thereafter, the reaction mixture was heated with stirring in an oil bathmaintained at 70°-75° C for 3.5 hr. After cooling to ambient conditions,the excess thionyl chloride was removed in vacuo. The resulting solidwas stirred with an ice-water mixture (2 1) at 15°-20° C for 2 hr. Thesolid was then collected by suction filtration, washed with water (800ml) and dried in vacuo to give 44.5 g (83.3% yield) of crude product,which was extracted with boiling heptane. Upon cooling the heptaneextract deposited 2,4-dichloro-6-phenyl-s-triazine in several crops.Total amount of product was 39.5 g, (73% yield), mp 117.5°-120° C; mp121° C (H. Albers et al, German Patent 1,178,052; Chemical Abstracts,61, 16080 (1964); mp 120°-120.5° C (R. E. Jones et al. AD 229453, Sept.1959).

EXAMPLE 4 2,4-DIAZIDO-6-PHENYL-S-TRIAZINE

A mixture (prepared in a inert atmosphere enclosure) of sodium azide(19.57 g, 0.3 mol), lithium azide (1.0 g, 0.0204 mol),2,4-dichloro-6-phenyl-s-trazine (23.0 g, 0.102 mol) and acetonitrile(400 ml) was stirred at ambient conditions under a nitrogen atmospherefor 160 hr. Filtration gave 33.5 g of insoluble materials, whereasevaporation of the filtrate using a rotary evaporator afforded 9.2 g ofmaterial which was crystallized from heptane yielding 8.0 g of2,4-diazido-6-phenyl-s-triazine, mp 130°-131° G. The insoluble materialwas extracted with boiling heptane which upon partial evaporation andcooling, afforded 12.8 g of material, mp 128.2°-131° C. Crystallizationfrom heptane gave 12.2 g of 2,4-diazido-6-phenyl-s-triazine, mp130°-132° C. Total yield of 2,4-diazido-6-phenyl-s-triazine was 20.2 g,(85.5% yield), mp 130°-132° C. The melting point and infrared spectrumwere identical with that of the authentic sample.

EXAMPLE 5 PREPARATION OF TRIMETHYLSILYL AZIDE

The procedure employed was a variation [Paciorek et al, Inorg. Chem.,4,1767 (1965)] of the method used by West and Thayer R. West et al, J.Am. Chem. Soc., 84, 1763 (1962)]. Trimethylsilyl chloride was purifiedby distillation through a one meter spinning band column with 40%take-off, bp 58°-59° C/763 mm. To trimethylsilyl chloride (215 g, 1.98mol) in diglyme (352 ml) was added sodium azide (158 g, 2.42 mol). Theresulting mixture was allowed to stand at room temperature withoccasional shaking over a period of 8 days. Thereafter, the mixture wassubjected to vacuum distillation at room temperature and the distillate(163.2 g, 74% yield) was collected in a Dry Ice trap. The crudetrimethylsilyl azide was fractioned over a 1 meter spinning band columnusing 40% take-off, bp 97° C/760 mm.

EXAMPLE 6 PREPARATION OF DIPHENYLPHOSPHINYL CHLORIDE

Diphenylchlorophosphine (200 ml, 246 g, 1.12 mol) was heated withstirring at 100° C and through this solution was bubbled gaseous oxygendried by passing through towers filled with phosphorus pentoxide andDrierite. This process was performed over a period of 31 hr. The crudeproduct was distilled in vacuo through a short Vigreaux column, thefraction with bp 164°-168° C at 0.02 mm, 212 g (80.3% yield), exhibitedan infrared spectrum identical to that of an authentic sample.

EXAMPLE 7 PREPARATION OF DIPHENYLPHOSPHINYL AZIDE

Following a previously [Paciorek et al, Inorg. Nucl. Chem. Letters, 2,39 (1966)] developed procedure, diphenylphosphinyl chloride (14.87 g,62.86mmol) was introduced into a tube (in the inert atmosphereenclosure). Trimethylsilyl azide (10.45 g, 90.69 mmol) was thencondensed onto this material on a vacuum line at liquid nitrogentemperature. The tube was sealed in vacuo and heated at 60° C for 48 hr.Thereafter, it was cooled, opened to a vacuum system and the volatileswere collected in a liquid nitrogen trap (originally without pumping atroom temperature, finally with pumping at 70° C). The total timerequired to remove the volatiles (excess (CH₃)₃ SiN₃ and the by-product(CH₃)₃ SiCl) was 16 hr. A quantitative yield of pure diphenylphosphinylazide was realized.

EXAMPLE 8 PREPARATION OF TRIPHENYLSILYL AZIDE

Following the method of Wiberg et al [Wiberg et al, Angew. Chem.Internat'l Ed. Engl., 1, 335 (1962)] in an inert atmosphere enclosure asolution of triphenylsilylchloride (73.9 g, 0.251 mol) intetrahydrofuran (400 ml) was stirred with lithium azide (15.3 g, 0.312mol) at room temperature over a period of 115 hr. After filtration, thesolvent was removed in vacuo. The resulting white solid was boiled withheptane (350 ml), filtered hot and allowed to crystalline.Triphenylsilyl azide, 65.5 g (86.3% yield), mp 82°-84° C was obtained.The melting point and infrared spectrum were identical with that of anauthentic sample.

EXAMPLE 9 PREPARATION OF DIPHENYL-P-STYRYLPHOSPHINE

In a 500 ml round bottom flask equipped with stirrer, reflux condenser,thermometer, and nitrogen by-pass were placed 17.74 g (0.741 mol) ofmagnesium turnings in a dry nitrogen atmosphere. To this were added 2.7ml of ethyl bromide dissolved in 10 ml of dry tetrahydrofuran at 31°-53°C over a period of 15 min. After stirring for an additional hr andsubsequent cooling to 5° C, 50 g of p-chlorostyrene, dissolved in 80 mlof dry tetrahydrofuran were added over a period of 70 min with icecooling at such a rate that the temperature of the solution neverexceeded 23° C. The mixture then was stirred for 1.5 hr at roomtemperature before being transferred into a dropping funnel inside aninert atmosphere enclosure. This solution then was added in a nitrogenatmosphere to 67.9 g diphenylchlorophosphine dissolved in 250 ml drytetrahydrofuran at 6°-9° C over a 30 min. period. The reaction mixturewas subsequently stirred at room temperature for 1 hr., cooled to 6° C,and hydrolyzed by adding a solution of 72.5 g ammonium chloride in 500ml of deaerated water. After separating the organic layer from theaqueous phase and washing the latter with two 250 ml portions oftetrahydrofuran the combined organic solutions were dried over sodiumsulfate overnight. After filtration the volume of the solution wasreduced to 50% by evaporating the solvent, whereupon heptane was addedto precipitate any polymer present. Since no precipitate formed thesolution was evaporated to dryness and the remaining viscous oil treatedin a nitrogen atmosphere with boiling ethanol. In this manner 30.2 g(34%) of ethanol insoluble material (probably polymer) were obtainedwhereas from the ethanolic filtrate, after addition of water andcooling, 51.2 g (57.7%) of diphenyl-p-styrylphosphine, mp 77°-78° C,were isolated.

II. PREPARATION OF OXIDIZED STYRYLPHOSPHINE MONOMER EXAMPLE 10

Attempted preparation of (c₆ h₅)₂ p(o)n═p(c₆ h₅)₂ c₆ h₄ ch═ch₂

to a stirred solution of diphenyl-p-styrylphosphine (1.0 g, 3.468 mmol)and 0.2g. of 4-t-butylpyrocatechol (a polymerization inhibitor) intetrahydrofuran (20 ml) under an inert atmosphere was addeddiphenylphosphinyl azide (0.84 g, 3.468 mmol) in tetrahydrofuran (20 ml)over a period of 1 hr. Nitrogen evolution was observed. Stirring at roomtemperature was continued for a total of 14 days; since thedisappearance of the azido group, as evidenced by infrared spectroscopy,proceeded very slowly. After removal of the solvent, a gummy productindicating the presence of polymeric material, was obtained. Theattempted isolation of the monomeric product (C₆ H₅)₂ P(O)N═P(C₆ H₅)₂ C₆H₄ CH═CH₂ was unsuccessful.

EXAMPLE 11 PREPARATION OF (C₆ H₅ O)₂ P(O)N═P(C₆ H₅)₂ C₆ H₄ CH═CH₂

To a stirred solution of diphenyl-p-styrylphosphine (10.0 g, 34.68 mmol)and 0.2g of 4-t-butylpyrocatechol (a polymerization inhibitor) intetrahydrofuran (100 ml) under an inert atmosphere was added a solutionof diphenylphosphoryl azide (9.54 g, 34.66 mmol) (which was obtainedfrom Willow Brook Labs., Inc., Waukesha, WI, and used as received) intetrahydrofuran (100 ml) over a period of 3 hr, immediate evolution ofgas was observed. The solution was then stirred at room temperature for120 hr. Thereafter, the solvent was removed in vacuo; crystallizationfrom benzene-heptane gave 14.35 g of product (77.3% yield), mp 150°-152°C. Anal. calcd for C₃₂ H₂₇ P₂ NO₃ : C, 71.77%; H, 5.08%; P, 11.57%; N,2.62%; O, 8.96%; MW 535.53 Found: C, 71.87; H, 5.35; P, 11.51; N, 2.60,MW 569.

III. BULK POLYMERIZATION OF OXIDIZED STYRYLPHOSPHINE MONOMER EXAMPLES12-22

Styrylphosphine monomer oxidized by diphenylphosphorylazide,2,4-diazido-6-phenyl-s-triazine and 2-azido-4,6-diphenyl-s-triazine(Examples 12-16, 17-18 and 19-22 respectively) were bulk polymerizedunder the conditions described in Table I below. All of thepolymerization reactions were conducted in evacuated ampoules (10⁻³ mm?)in a vacuum line. After completion of each reaction, the residue in eachampoule was extracted with about 10 ml of chloroform, and the solublepolymer was precipitated by treatment of the chloroform solution withheptane, filtered and dried.

                                      Table I                                     __________________________________________________________________________    SUMMARY OF BULK                                                               POLYMERIZATIONS CONDUCTED                                                     ON PRE-OXIDIZED MONOMERS                                                      Ex-  Monomer           Conditions                                                                            Polymer                                        ample               Amt                                                                              Temp                                                                              Period                                                                            Yield                                                                             MP                                         No.  Identification g  ° C                                                                        h   %   ° C                                                                         MW                                    __________________________________________________________________________    12  (ΦO).sub.2 P(O)N=PΦ.sub.2 ΦCH=CH.sub.2                                            0.41                                                                             230 1.5 (90).sup.a                                                                        108-125                                                                            n.a..sup.b                            13  (ΦO).sub.2 P(O)N=PΦ.sub.2 ΦCH=CH.sub.2                                            1.00                                                                             150 1.0 76  145-162                                                                            56300                                 14  (ΦO).sub.2 P(O)N=PΦ.sub.2 ΦCH=CH.sub.2                                            1.00                                                                             150 5.0 74  139-156                                                                            100000                                15  (ΦO).sub.2 P(O)N=PΦ.sub.2 ΦCH=CH.sub.2                                            1.00                                                                             150 24  82  118-156                                                                            46200                                 16  (ΦO).sub.2 P(O)N=PΦ.sub.2 ΦCH=CH.sub.2                                            15.5                                                                             165 5.0 73  122-143                                                                            54500                                                                (13)                                                                              --   --                                    17  ΦC.sub.3 N.sub.3 [N=PΦ.sub.2 ΦCH=CH.sub.2 ].sub.2                                 1.00                                                                             130 5.0 n.r..sup.c                                                                        n.a.  n.a.                                 18  ΦC.sub.3 N.sub.3 [N=PΦ.sub.2 ΦCH=CH.sub.2 ].sub.2                                 1.00                                                                             160 5.0 16  195-214                                                                            --                                                                   (66)                                                                              >295 --                                    19  Φ.sub.2 C.sub.3 N.sub.3 N=PΦ.sub.2 ΦCH=CH.sub.2                                   1.04                                                                             190 5.0 82  218-222                                                                            --                                    20  Φ.sub.2 C.sub.3 N.sub.3 N=PΦ.sub.2 ΦCH=CH.sub.2                                   5.00                                                                             190 5.0 84  215-226                                                                             6600                                 21  Φ.sub.2 C.sub.3 N.sub.3 N=PΦ.sub.2 ΦCH=CH.sub.2                                   2.04                                                                             230  0.75                                                                             90  225-240                                                                            10400                                 22  Φ.sub.2 C.sub.3 N.sub.3 N=PΦ.sub.2 ΦCH=CH.sub.2                                   0.70                                                                             230 5.0 76  215-230                                                                             9500                                 __________________________________________________________________________     .sup.a The number in the parentheses corresponds to the yield of              chloroform insoluble polymer.                                                 .sup.b Not applicable.                                                        .sup.c No reaction.                                                      

The results in the Table above show that homopolymers of very goodmolecular weight characteristics were obtained from the styrylphosphinemonomer oxidized with diphenylphosphorylazide. These homopolymers (Exs.12-16) could readily be formed into moled articles and films

EXAMPLES 23-28

As shown in Table 2 below, a series of copolymers (Exs. 23-26) andterpolymers (Exs. 27-28) were prepared by the bulk polymerization of theoxidized monomers indicated under the conditions shown. Allpolymerization reactions were conducted in evacuated ampoules in themanner described for Examples 12-22. The soluble polymer in each examplewas isolated as also described for Examples 12-22.

                                      TABLE 2                                     __________________________________________________________________________    SUMMARY OF BULK COPOLYMERIZATIONS AND TERPOLYMERIZATIONS                        Monomer A              Monomer B         Monomer C                          Ex-                 Amt               Amt               Amt                   ample                                                                             Identification  g  Identification g  Identification g                     __________________________________________________________________________    23  (ΦO).sub.2 P(O)N=PΦ.sub.2 ΦCH=CH.sub.2                                            2.00                                                                             ΦC.sub.3 N.sub.3 [N=PΦ.sub.2 ΦCH=CH.sub                           .2 ].sub.2     0.31                                                                             n.a..sup.a     n.a.                  24  Φ.sub.2 PΦCH=CH.sub.2                                                                 1.03                                                                             Φ.sub.2 C.sub.3 N.sub.3 N=PΦ.sub.2                                    ΦCH=CH.sub.2                                                                             2.00                                                                             n.a.           n.a.                  25  Φ.sub.2 C.sub.3 N.sub.3 N=PΦ.sub.2 ΦCH=CH.sub.2                                   2.07                                                                             ΦC.sub.3 N.sub.3 [N=PΦ.sub.2 ΦCH=CH.sub                           .2 ].sub.2     0.15                                                                             n.a.           n.a.                  26  Φ.sub.2 C.sub.3 N.sub.3 N =PΦ.sub.2 ΦCH=CH.sub.2                                  16.92                                                                            Φ C.sub.3 N.sub.3 [N=PΦ.sub.2 ΦCH=CH.su                           b.2 ].sub.2    1.23                                                                             n.a.           n.a.                  27  (ΦO).sub.2 P(O)N=PΦ.sub.2 ΦCH=CH.sub.2                                            2.24                                                                             Φ .sub.2 C.sub.3 N.sub.3 N=PΦ.sub.2                                   ΦCH=CH.sub.2                                                                             0.74                                                                             ΦC.sub.3 N.sub.3 [N=PΦ.su                                             b.2 ΦCH=CH.sub.2 ].sub.2                                                                 0.53                  28  (ΦO).sub.2 P(O)N=PΦ.sub.2 ΦCH=CH.sub.2                                            2.00                                                                             Φ.sub.2 C.sub.3 N.sub.3 N=PΦ.sub.2                                    ΦCH=CH.sub.2                                                                             1.10                                                                             ΦC.sub.3 N.sub.3 [N=PΦ.su                                             b.2 ΦCH=CH.sub.2 ].sub.2                                                                 0.17                                                     Conditions                                                                           Polymer                                                      Ex- Mole Ratio                                                                          Temp                                                                             Period                                                                            Yield                                                                             MP       TGA                                             ample                                                                             A : B : C                                                                           ° C                                                                       h   %   ° C                                                                         MW  Fig.                   __________________________________________________________________________                                                           No.                                                                           --                                                                            --                                              23  9.2 : 1.0                                                                           165                                                                              5.00                                                                              (82).sup.b                                                                        > 295                                                                              n.d..sup.c                                                                        13                                                               4   92-100                                                                             n.d.                                                                              --                                              24  1.0 : 1.0                                                                           230                                                                              0.75                                                                              80 194-204                                                                        15300                                                                              14                                                  25  20.4 : 1.0                                                                          230                                                                              1.00                                                                              (4a)                                                                              > 260    16                                                               50  206-323                                                                            4300                                                                              15                                              26  19.6 : 1.0                                                                          230                                                                              2.0 (79)                                                                              240- 370 17                                                               14  187-100                                                                            3400                                                                              18                                              27  6.0 : 2.0 : 1.0                                                                     178                                                                              5.0 (86)                                                                              > 295    19                                                               3   155-165                                                                            3900                                                                              --                                              28  6.0 : 3.3 : 0.35                                                                    173                                                                              5.0 (87)                                                                              > 295    20                                                               5   115-130                                                                            4800                                                                              --                     __________________________________________________________________________     .sup.a Not applicable                                                         .sup.b The number in the parentheses corresponds to the yield of              chloroform insoluble polymer                                                  .sup.c Not determined.                                                   

IV. BULK POLYMERIZATION OF DIPHENYL-p-STYRYLPHOSPHINE EXAMPLES 29-43

Diphenyl-p-styrylphosphine was polymerized by a bulk procedure under theconditions shown in Table 3 below in the quantities shown. Allpolymerization reactions were conducted in evacuated ampoules either insealed ampoules (Exs. 29-34) or in ampoules attached to a vacuum line(Exs. 35-43). The polymeric material at the completion of each reactionwas extracted with chloroform and isolated in the manner described forExamples 12-22.

                  TABLE 3                                                         ______________________________________                                        SUMMARY OF BULK POLYMERIZATIONS CONDUCTED                                     ON DIPHENYL-p-STYRYLPHOSPHINE                                                 Ex-             Conditions  Polymer                                           ample Monomer   Temp    Period                                                                              Yield MP                                        No.   g         ° C                                                                            h     %.sup.a                                                                             ° C                                                                           MW                                 ______________________________________                                        29    1.21      230      0.75 69    140-165                                                                              67000                              30    0.75      230      0.75 72    133-149                                                                              47000                              31    0.76      230     1.5   80    130-140                                                                              28600                              32     12.49    230     1.0   81    125-146                                                                              18000                              33    1.10      230     0.3   77    122-145                                                                              27000                              34     12.15    230     0.75  87    127-140                                                                              31600                              35    1.50      180     0.5   73    104-148                                                                              23300                              36    2.00      210     0.5   77    126-135                                                                              16400                              37    2.00      230     0.5   70    128-138                                                                              11100                              38    2.00      250     0.5   58    120-136                                                                              9000                               39    2.00      100     24.0  6.sup.b                                                                             135-145                                                                              34000                              40    2.00      100     8.0    16.sup.b                                                                           125-135                                                                              12300                              41    2.00      100     1.0    23.sup.c                                                                           127-135                                                                              8700                               42     2.00.sup.d                                                                             210     0.5   65    140-150                                                                              28200                              43    2.00      210     0.5   68    135-143                                                                              15200                              ______________________________________                                         .sup.a This is the yield of chloroform soluble polymer.                       .sup.b The low yield of the chloroform soluble polymer is due to high gel     formation.                                                                    .sup.c The low yield obtained here is due to low conversion of the            starting monomer.                                                             .sup.d This diphenyl-p-styrylphosphine was prepared in the absence of the     polymerization inhibitor, 4-tert-butylpyrocatechol.                      

V. PREPARATION OF PHOSPHAZENE GROUP CONTAINING POLYMERS BY OXIDATION OFPREFORMED POLYMERS OF STYRYLPHOSPHINE

The following procedures are representative of those employed for thesynthesis of substituted ("oxidized") homopolymers and copolymers shownin Table 4. The styrylphosphine polymers prepared in Examples 29-43 wereused in the oxidation reactions.

EXAMPLE 44 ##STR9##

To a stirred solution of polydiphenyl-p-styrylphosphine (2.00 g, 6.936mmol) in tetrahydrofuran (40 ml) was added diphenylphosphoryl azide(1.91 g, 6,934 mmol) in tetrahydrofuran (40 ml) over a period of 1 hrunder an inert atmosphere. Nitrogen gas evolution was observedimmediately. The solution was then stirred overnight at roomtemperature. Subsequently, the polymer was precipitated from solutionwith heptane (250 ml), filtered and dried in vacuo for 7 hr at 103° Caffording 3.31 g (89% yield) of product, mp 142°-166° C; MW>50000.

EXAMPLE 45 ##STR10##

To polydiphenyl-p-styrylphosphine (9.50 g, 32.95 mmol) intetrahydrofuran (180 ml) was added diphenylphosphinyl azide (7.61 g,31.29 mmol) in tetrahydrofuran (45 ml) under an inert atmosphere. Theresulting solution was stirred at room temperature for 8 days.Subsequently, to the solution was added 2-azido-4,6-diphenyl-s-triazine(0.45 g, 1.64 mmol). After stirring at room temperature for 24 hr thesolution was poured onto heptane (500 ml). The precipitated product wasfiltered and dried in vacuo at 122°-155° C for 10 hr giving 15.52 g (93%yield) of polymer, mp 198°-222° C; MW 54600.

EXAMPLE 49 PREPARATION OF CANDIDATE TERPOLYMER

To polydiphenyl-p-styrylphosphine (2.00 g, 6.936 mmol) intetrahydrofuran (20 ml) was added diphenylphosphoryl azide (1.527 g,5,549 mmol) in tetrahydrofuran (20 ml) under an inert atmosphere. Theresulting solution was stirred at room temperature for 5 days. Then tothe solution was added 2-azido-4,6-diphenyl-s-trazine (190 mg, 0.694mmol). After 2 hr this was followed by 2,4-diazido-G-phenyl-s-triazine(41.3 mg, 0.173 mmol). Subsequently, after stirring for 14 hr at roomtemperature, an additional quantity of 2-azido-4,6-diphenyl-s-triazine(95.0 mg, 0.347 mmol) was introduced. The resulting solution, followingstirring at room temperature for 6 hr, was poured onto heptane (200 ml).The precipitated product was filtered and dried in vacuo at 90°-93° Cfor 9 hr giving 3.39 g (93% yield) of polymer, mp 153°-170° C; MW 91300.

    Table 4      HOMOPOLYMERS, COPOLYMERS, AND TERPOLYMERS OBTAINED VIA "OXIDATION" OF     PREFORMED POLY(DIPHENYL-p-STYRYLPHOSPHINE) Starting Material Ex-  MP     No. TGA  No. ample Composition °      C MW Units FIG. MW Units                   44      ##STR11##      142-166 >50000  93 21 11300 39      45     ##STR12##      198-222  54600 102 22 18000 62      46     ##STR13##      240-282  n.d..sup.a -- 23 31600 110      47     ##STR14##      205-220  23500 46 24 31600 110      48     ##STR15##      202-215  n.d. -- 25 31600 110      49     ##STR16##      158-170  91300 171 26 31600 110      50     ##STR17##      170-180  25800 48 27 15000 52      51     ##STR18##      170-192  38000 71 28 16000 55      52     ##STR19##      170-215     .sup.a The molecular weight of this polymer could not be determined due t     its insolubility in the solvents tried.

In the formation of the terpolymers (Exs. 46-52) not all of the2-azido-4,6-diphenyl-s-triazine was added in the second step of theoxidation sequence. This is described in detail above for Example 49.The reason for this was to ensure that when the diazide oxidizing agentwas added, that a sufficient number of sites remained to permitinterchain linking to take place (scheme I); not intramolecular reaction(scheme II.

    ______________________________________                                        SCHEME I                                                                      ______________________________________                                         ##STR20##                                                                    ______________________________________                                    

    ______________________________________                                        SCHEME II                                                                     ______________________________________                                         ##STR21##                                                                     ##STR22##                                                                    ______________________________________                                    

It can be readily determined from the data in Table 4 that terpolymersof very substantial molecular weight and good processing properties wereobtained by oxidation of preformed polystyrylphosphine.

VI. TOXICOLOGICAL TESTING

The toxicological effects of the thermal degradation products of threerepresentative styrylphosphine polymers of the present invention weretested. Samples of polymers of Examples 16, 26 and 45 were formed into20-27 washers of 0.709 outside diameter with a center hole of innerdiameter 0.25 and 0.08 average thickness. The amounts of materialssubmitted for testing varied between 9.25g and 13.10g. In the test, ratswere subjected to thermal degradation products of each polymer material,and no mortalities were observed.

                  TABLE 5                                                         ______________________________________                                             Wt. of Polymer                                                                              Pyrolysis                                                                              CO Content of Pyrolysis                           Ex.  Sample (g)    Temp. ° C                                                                       Gas (mg/m.sup.3)                                  ______________________________________                                        16   3.0 g         500      393 (305 ppm)                                          5.34                   174 (174 ppm)                                     26   3.0           550      348 (270 ppm)                                          5.27                   683 (530 ppm)                                     45   3.0           550      515 (400 ppm)                                          6.82                                                                     ______________________________________                                    

VII. MOLDING STUDIES

A number of polymeric compositions as shown in Table 6 below werecompressed in a molding device in combination with a Carver LaboratoryPress, Model C. All polymer samples in Table 6 below were ground in amortar before being placed into the mold.

                  TABLE 6                                                         ______________________________________                                        Molding Conditions                                                                   Contact                                                                              Initial Lead                                                                             Final Lead                                                Temp    Time           Time      Time                                    Ex.  ° F                                                                            min      lbs   min  lbs  min   Remarks                           ______________________________________                                        45   340     10       500   1    1000 4     Very                                                                          good                                                                          washers                           16   260     10       500   1    1000 4     Very                                                                          good                                                                          washers                           26   440      5       500   5    --   --    Accept-                                                                       table                                                                         but                                                                           brittle                                                                       washers                           44   260     --       10000 0.5  --   --    Clear                                                                         film.sup.b                        45   270     10       1000  1    2000 4     Good                                                                          washer                            18   400     10       500   5               Opaque,                                                                       brittle                                                                       washer                            23   360     10       500   5               Accep-                                                                        table                                                                         washer                            48   440     10       750   5               Very                                                                          good                                                                          clear                                                                         washer                                 360     10       750   5               Very                                                                          good                                                                          clear                                                                         washer                            ______________________________________                                         .sup.a The pressure used here was just contact pressure, this operation       was performed to bring the sample up to temperature.                          .sup.b In this instance no mold was used, the powdered sample was placed      on on aluminum plates and was pressed.                                   

Having now fully described the invention, it will be apparent to one ofordinary skill in the art that many changes and modifications can bemade there to without departing from the spirit or scope of theinvention as set forth herein.

What is claimed as new and intended to be secured by Letters Patentis:
 1. A process for treating homopolymers, copolymers and terpolymersof styrene based monomers, which comprises:polymerizing orcopolymerizing p-diphenylphosphinestyrene by bulk or solventpolymerization procedures; and oxidizing said polymerizedp-diphenylphosphinestyrene with at least one organoazide selected fromthe group consisting of (C₆ H₅)₂ P(O)N₃, (C₆ H₅ O)₂ P(O)N₃, (C₆ H₅) C₃N₃ (N₃)₂ and (C₆ H₅)₂ C₃ N₃ (N₃).
 2. The process of claim 1 wherein saidp-diphenylphosphinestyrene is polymerized at a temperature of 100° to230° C.
 3. The process of claim 1, which comprises: reactingdiphenylphosphoryl azide with polydiphenylstyrylphosphine.
 4. Apolymeric composition prepared by oxidizing saidp-diphenylphosphinestyrene with any two of said organoazides as setforth in claim
 1. 5. The polymeric composition of claim 3, prepared bysequentially reacting 50 to 90 mole % of (C₆ H₅ O)₂ P(O)N₃ with a unitamount of polydiphenylstyrylphosphine and then reacting 50 to 10 mole %of (C₆ H₅)₂ C₃ N₃ (N₃) with the partially oxidizedpolydiphenylstyrylphosphine.
 6. A polymeric composition prepared byoxidizing said p-diphenylphosphinestyrene with any three of saidorganoazides as set forth in claim
 1. 7. The polymeric composition ofclaim 6, which has the formula ##STR23## wherein x is 50-90 molepercent, y is 36-15 mole percent and z = 10-2 mole percent.